The demister in my 77 Beta is not working. Firstly, the power connection to the window has come unstuck. Is there a way of reconnecting this with some sort of super metal adheasive to see if power can be transferred.

Next, is there a way of testing if the demisting threads actually work.

Given the worst that they do not work, how difficult is it to change the rear window and of course to source a replacement that actually can be tested as working.